Security at level crossings has been an issue since the first trains have set wheels on the face of the earth. In addition to warning lights and audio signals, one of the first, and to this day, still widely and almost uniquely used solution, is to provide pivotable barriers on both sides of the railway track. As it is believed to be well known, such barriers are automatically lowered before the passage of a train to block the path on both sides and then raised after the train is passed.
Even though this gate system has been found effective to visually alert travellers of the incoming passage of a train at a level crossing, it does not alert of the presence of a vehicle already positioned on the railway before the lowering of the gates or of a smaller vehicle or a pedestrian that could have decided to ignore the gates and accompanying visual and sound alarm signals and still cross the track.
A presence detection system for level crossing and more generally to path crossing allowing additional functionalities and flexibilities than such a system is therefore desirable.